Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Selection of study subjects from the initial primary care diagnostic centres' spirometry databases. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; LLN: lower limit of normal. * based on Swanney prediction equations for FEV1/FVC [6] † subgroups D, E, and F in Figure 2b ‡ subgroups A, B, and C in Figure 2b.
